Be careful with bit depths, not all as it seems. Welcome to SETI Astro. So here we are in Affinity Photo.
I'm sure a lot of you are familiar with it. And I've been trying and trying to get the exports out of this to work properly with Cosmic Clarity, Sharpen, and Denoise. And... I finally got it to work with 16-bit outputs, and I really wanted it to work with 32-bit outputs. So here's the export window you get when you go to File, Export.
You can go down to the Advanced Features and save it as a 32-bit RGB, which I did. Now I went ahead and I'm going to run Cosmic Clarity. I'll just do it on Stellar. It recognizes it as a 32-bit unsigned TIFF. It goes ahead and sharpens it just fine and saves it as a 32-bit unsigned TIFF.
But now when we go to open what it had saved, we just get this big awful mess and I couldn't figure out what was going on. So I decided to do a little test. All I did was open the output from Affinity as the 32-bit TIFF and PixInsight so I can look at the histograms and stuff.
And the output is this grayish image. If you open it in Affinity Photo, it looks just fine. But in something like PixInsight, we could pull up the histogram.
It's just this little bit of the histogram here. There's no data below and above it. We can go ahead and stretch it. And what you're going to start seeing are these jagged chunks.
And to me, that was very indicative of the data itself not being saved as 32-bit TIFF, but as 16-bit information just in the 32-bit architecture. So then I made just a little snippet of code. All it's going to do is dump all the metadata from the tiff file that Affinity Photo saved.
So when we run our little snippet of code, we get a bunch of stuff. This is all the all the metadata that's saved with our particular tiff file. And we can see here, some important things it does say it is an integer 32 bits.
save. So that looks all good. It looks like we're 32 bits per channel.
That's also good. And then we see this strip offsets. Lots of data in here for strip offsets.
And then the bit depth saved in each strip. And we continue on down. We see some other color space data that's been saved. But really importantly here, the XFTAG color space, 65, 535. What that's telling us is the color space itself is only 16-bit and all this offset data in here is just buffer.
It's telling you where to start looking for actual data on each of the rows because the data is only 16 bits stored in a 32-bit architecture. That is the reason why Cosmic Clarity is having such a hard time figuring out what to do with these 32-bit images from Affinity. It's because they're actually not 32-bit. What you need to do to make Cosmic Clarity work for you is just go ahead and save your image as a 16-bit RGB TIFF.
So if we go ahead and export, we want... a 16-bit RGB TIFF now. We'll go ahead and export that into our input folder for Cosmic Clarity. Now we can go ahead and run Cosmic Clarity, recognize it as a 16-bit TIFF.
It does this sharpening. and saved it as a 16-bit TIFF. Now if we go ahead and open our output file, now we have an actual output file. The other thing we could do is look at the actual 16-bit TIFF file it saved. the histogram for it.
So here's the 16-bit TIFF file. Notice how smooth the histogram is now versus these blocks of data from the 32-bit save. So for those of you using Affinity Photo out there, 16-bit exporting is truly all the more you're going to be able to export as far as bit depth.
Don't save it as a 32-bit TIFF. All it's doing is buffering and making larger file sizes for you. Save it as a 16-bit TIFF. You should be able to run Cosmic Clarity, Cosmic Denoise, and work with SETI Astro Suite just fine. I hope those of you using Affinity out there found this informative.
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